Large-capacity telephone system



July 13 1926. 1,592,684

' w. w. OWEN LARGE CAPACITY TELEPHONE SYSTEM Original Fil uly 12, 1920 2 Sheets-Sheet 1 IZ'LUEHZUP M1152 Mg; [711115;-

July 13,1926. 1,592,684.

W. W. OWEN LARGE cAPAcITx TELEPHONE SYSTEM .Ofizina] Fil y 12. 1920 2 Sheets- Sheet 2 lnfiZZ WHITE? Ewen ZZMW 5 Patented July 13, 1926.

UNITED STATES PATENT OFFICE.

WILLIAM WALTER OWEN, OF OAK PARK, ILLINOIS, ASSIG-NOB, BY MES NE ASSIGN- MENTS, TO AUTOMATIC ELECTRIC INC, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

LARGE-CAPACITY TELEPHONE SYSTEM. i

Application filed July 12, 1920, Serial No. 395,543. Renewed January 26. 1925.

My invention relates in general to large capacity automatic telephone systems, and more particularly to an improved telephone system in which any of the switches in the system may be doubled in capacity and in which a calling device of a new type is used which permits a calling subscriber to choose any group of trunks of lines in one of these specially designed switches.

Among the obiects of my invention therefore is to provide greater capacity for a telephone system without complicating the circuits to any great extent, and to so arrange the circuits and operations as to give such large capacity to a subscriber without in-- creasing the number of digits in the called subscribers number. This provides a very simple system of numbering for a system which may be used in large exchanges. In order to provide such a. system I propose the use of first selector switches having access to two groups of 100 trunks each, second selectors also having access to two groups of 100 trunks each, and connector switches having access to four groups of 100 lines each; the selectors are so arranged as to require the transmission of only one digit in spite of their greater trunking capacity and the connectors require only two digits as is standard practice. It is well known that in the standard systems using first and second selectors and connectors of 100 capacity the subscriber would have access to 10,000 lines, using four digits. WVhilein my improved system a subscriber may have access to 160,000 lines by using only four digits. In each selector I provide a special switching relay normally short .circuited which when operated,

switches the incoming'line to an alternate.

set of wipers so that the connection will then be extended over the said wipers to a trunk line in the second hundred trunks. The line relay of each switch controls a pair of I" e I c springs which normally follow the usual 1mpulses to maintain the switching relay short clrcuited. The calling devlce has two sets of holes, one designated by letters and the other by figures and has a special finger lever which is operated when the lettered row of holes is used to send a short (or series of short) impulses to the line relay. In case these short impulses are received by the line relay, said relay will operate so rapidly that It will be understoodthat such switching relays may be added to any of the switches in the system, that is, only to the first selector to double the capacity of the system or only to the first and second selectors.

Referring now to the accompanying drawings Fig. 1 shows a calling device of my improved type having a finger lever for send- .70

ing a short or quick impulse when the mechanism is controlled by the lettered row of holes.

F ig. 2 shows a calling station A equipped with a dial (not shown) of the type illus- I trated in Fig. 1, and having access through a line switch C to selector switches such as D. The switches D in turn have access to second selectors E.

Fig. 3 shows one of the connector switches H having access to I00 lines and being ac- Cessible-to the second selectors E.

I will now explain the operation of the circuits and devices shown, more in detail, reference being had to the drawings.

The calling device of Figure 1 is of standard'two wire type of callingdevice such as is shown in British Patent. No. 29654 of 1910. That is, the finger of the operator is first inserted in one of the finger holes, the dial is thenrotated in a clockwise direction until the finger meets the stop 2 at which time the dial-is released and rotates back in a counter-clockwise direction to senda series of impulses over the line circuit. The impulses are kept of a standard length by a governor which controls the backward movement of the dial. It is to be understood that when the dial is operated by means of the two holes 1 or A the operation of the calling device on its backward movement will be the same in either case, that is, one impulse will be sent. However when the subscriber uses any of the lettered holes to operate he will press down the finger lever 3 just before releasing the dial. The finger lever 3 may be mounted on the under side of the dial in any manner, its function being to cause a momentary vibration of the only for a short time about one third of the usual impulse of the callingdevice. The trigger 6 on the end of lever' is normally held by a light spring 7 against a stop 8 so that as the left hand end of lever 3 moves up the spring will be bent and then released by the trigger 6 slidingover the end of spring 5', thus causing it to vibrate and momentarily open, contact. As the lever 3 returns... however, the trigger 6; is rotated. about its. pivot against the tension of the light spring 7' without having any eiiect on the springs. 4t. and 5. I

An arrangement similar to the above, except that it is. adapted to transmit the high. speed impulses after the regular impulses, is shown in U. S. Patent No. 1,345,054, granted June 29'. 1920'. to B. D. Villis.

Now when the subscriber at A. attempts to make a call, assuming that the number of the subscriber he wishes to call is 2222. Then the call will proceed in the usual manner as follows. hen the receiver is removed a. circuit. is completed for the line relay 9; of the line switch C in series with the line of substation A. Relay 9? energizes toclose: a series circuit at springs 10 for the switching relay 11 and rotarymagnet 12. and also to close a circuit from private wiper 13 through springs 14 and 15., springs 16,. androtary magnet'l2 to battery. Should.

the trunk line, uponwhich the wipers of the switch C are now standing, be busy then ground Will be present on the wiper 13 and the magnet 12 will operate as a buzzer to advance the. wipers in search of an idle trunk, relay 11' being short circuited by the ground on wiper 13.. As soon as an idle. trunk line is reached relay 11 will no, longer be short 'circuited and. will energize over its previously traced circuiltyits high resistance preventing the operation of" magnet 12. Be lay 11 disconnects line relay Stand ground from thercalli'ng line and extends the connection tothe selector D. of the selected trunk line. Relay 9 remains energized. for an instant to hold relay 11 energized until ground is applied. to wiper 13'; from the relay'18 of the seized selector.

As soon as relay 11 thus extends the connection to the selectorD" a circuit is con1- pl'eted for the line relay 17 in series with the calling line. relay I7 energizes to close a circuit for relay 18, which supplies ground to the release trunk and also closes a circuit atsprings and 20 for therelay 21'. Relay 21 does not energize at this time. however, due. to a short circuit normally closed therefor through springs 19 and 22 ofrelav 17. The spring 22 is tuned or weighted so that it will follow the normal operations of the line relay 17 without breaking its contact with spring 19.

The subscriber will now operate his calling device by'using the #2 finger hole and will therefore not operate the special. finger lever 3, but will send two standard impulses to deenergize line relay 17 twice. Relay 17 completes the circuit of vertical magnet 23 each time it deenergizes inseries with slow relay 24-, to step both of its sets of line and private wipers X and Y to the second level of contacts. As relay 21 was not operated, only the wipers Y remain operative and it has therefore been determined that the call is to proceed to that half of the system accessible to wipers Y. Relay 2411 5011 energizing completes a circuit for rotary interrupter relay 25 from ground through springs of relay 1.8, springs 26 and 27. off normal springs 28, closed as soon asthe first vertical step is taken, and through relay 25' to battery. Relay 25 prepares a circuit for rotary magnet 29 at springs 30, and closes a locking circuit for itself through springs 31 and springs 32 of the rotary magnet.

Soon after the impulses for the first digit cease. relay 24 falls back and completes a circuit for rotary magnet 29 from ground through springs oi relay 18, spring 26 and its back contact. springs 30 and magnet 29 to battery. Magnet 29 operates to step the line and private wipers onto the first set of contacts in the selected level of trunks contact thereof then relay 25 will be again energized from ground on wiper 33, spring 34 and its back contact, spring 35 and its back contact. springs 36 of magnet 29. and through springs 28 and relay 25 to battery. Relay 25 again completes the circuit of rotary magnet 29 at springs 30 to step the wipers to the next trunk line. This alternate operation ofrelay 25 and magnet 29 coni-nues" until an idle trunk line is reached. at which time there will be no ground on wiper 33 and relay 25 will not again energize. A circuit now becomes effective from ground through springs of relay 18. relay 37, springs 36. springs 28, and relay 25 to' battery. It will be understood that relay 37' has previously been shorted but by the ground on wiper 33. Relay 37 energizes over this circuit, but its high resistance does o )ens the circuit of rela 18 which however remains in energized position until a ground isfed back from theseized second selector to hold relay 37 and the switch C in operated position. Relay 37 also opens a point in the circuit of the release magnet to prevent the release of the switch.

Now it is to be understood that the wipers X of this first selector D have access to an entirely different set of trunk lines than wipers Y and these trunk lines lead to selectors which have access to different connectors and hence different lines. Therefore the first digit determines in which half of the system the called line is located, by being either a letter or a figure.

As soon as the connectionis extended to selector E, whichis similar in all respects to the selector D, a circuit is completed for line relay 38 thereof in series with the calling line. Relay 38 closes a circuit for slow acting relay 39 and also a circuit forswitching relay 40. Relay 40 does not energize at this time however being short circuited as was relay 21 of selector E. Relay 39 however prepares a circuit for the vertical magnet 41, opens the release magnet circuit and connects ground to the release trunk to hold the preceding switches in operated position.

The operations of the selector E need not be explained in detail except that it operates in response to the impulses of the second digit of the called number, which being 2, does not permit the relay 40 to be operated and therefore the connection is extended over an idle trunk line in one of the ten groups to which the normally connected wipers 42, 43 and 44 have access, and over said trunk line to a connector switch such as H, (Fig. 3).

As soon as the connection is extended to the switch H the line relay 48 thereof energizes to complete the circuit of relay l9 which supplies ground to the release trunk to hold switches C, D and E operated and prepares a circuit for vertical magnet 51 in series with slow relay 50. It will he noticed that the line relay 48 of the connector also has a set of special springs similar to those controlled by the line relays of the selectors D and E which normally may control the relay 52 and may control relay 53 after the switch is operated vertically and the off normal springs 54 and 55 operate. However in the call being described, all the digits of the called number being figures, relay 48 will operate only in response to impulses of standard length and will'not permit springs 56 and 57 to open contact. Relay 48 operates first in response to the impulses of the third digit to complete a circuit for magnet 51 and relay 50 from ground through springs 58 and 59, springs 60 and 61, springs 62 and 63, and relay 50 and magnet 51 to battery. As: soon as magnet 51 steps the four sets of wipers their first verti-- cal step the off normal springs operate and the circuit of magnet 51 and relay 50 exposite the second level of contacts in their respective banks and relay 50 will fall back to prepare a circuit for the rotary magnet 6? and slow relay 68 in multiple. Plhen the line relay now responds to the impulses of the final digit of the called number a cir cuit will be closed from ground through springs 58 and 59, springs 60 and 61, springs 62 and 64, springs 65 and 69, springs 70, springs 71, and through relay c8 and magnet 67 in multiple to battery. Magnet 6? will be operated twice over this circuit to step all the sets of wipers into engagement with the second set of contacts in thesecond level of their respective banks. Relay 68 being slow acting maintains its armatures attracted for an instant after the wipers reach the desired contacts and therefore holds the busy test relay 72 connected to the test wiper 73. Should the desired line be busy then ground on the wiper 73 will cause relay 72 to operate and lock itself to ground, relay 72 will also open the rotary magnet circuit and connect the busy signalling machine with the calling line. Assuming the called line to be idle then relay 72 will not operate and when relay 68 falls back a circuit will be completed from ground through springs of relay 4:9, spring 74 and its back contact, upper winding of relay 75, spring 76 and its back contact, through private wiper 7 3, and through bridge cut off relay of the called line to battery through the rotary magnet. Relay and the cut oif relay now energize, relay 7 5 operating to lock itself energized and to switch the connection through to the line wipers 77 and 78 and thence to the called line. Generator current will now flow through the ringer of the called station through one winding of ring out off relay 79 and its back contacts. As soon as the called subscriber responds by removing his receiver, relay 79 will be energize-d in the usual manner to cut off the ringing current and close the talking circuit. Back bridge relay 92 will thereupon energize and feed talking current to the called subscriber.

It will be seen therefore that in case the called subscribers number consists wholly of figures and therefore the outside row of holes in the dial are used, that the operations of the entire system will be tandard and the connection will be extended over the normally connected set of wipers of each switch to a line or trunk in the lower banks of the several switches, assuming that the wipers having access to the lower bank of ea h switch are normally connected to the trunr; circuit through that switch. 7

If, however, the subscriber dials a called number which appears in the" directory as B222 then the calling man will first operate his: dial by using the finger hole marked B: which will first operate the: finger lever 3 onthe downward movement of the dial and! therefore cause a short opening of the line circuit by the vibration of the springs at. and 5. The line. circuit will at this time-be connected' to the line relay 17 of the selector D and therefore relay 17 will start to fall back but will be quickly energized again. that is, its armature will vibrate in synchronism. with the vibration of springs l and 5 of the calling device. This operation 0t relay 1? is not sullicient toallow its back contacts to. close and will not send an. impulse to the vertical magnet 23', but will. be sufiicient tocausethe spring 22 to open contact for an instant with its spring 19-, springs 19 and. 20 however remain closed: and relay 21 will now energize from ground through springs 19 and 20, relay 21, and resistance to battery. Relay 21 immediately opens springs 81 to permanently open the short circuit controlled by springs 19 and 22 and will lock itself energized? to the ground at springs of relay 18. Relay 21 now switches the trunk to selector D away from the wipers Y and into connection with the wipers X which as before pointed out have access to a: separate set of banks and therefore to the: other halt of the lines in: th systenn The remaining operations in calling. this number B222 are exactly the same as described in the prececL ing call except that in this case the call will proceed through a second selector similar to butof another group- In; case the; digit of the called number is 21322 thenthe call will be routedin a still different direction still sending the same number of opera-ting impulses to the switches That is, the first digit 2 will: operate selector D'without switching to the wipers X and the call will therefore pass to some selector similar to E and in the same half of the system with. E. In this case, however, the second digit being B, then the: springs l and? 5 will be operated while switch E is connected to the line and therefore relay 38 of switch E will permit th operation of switching relay 40 so that the connection will be extended via the second level of the upper set of banks of switch E to another group 0t connectors similar to H but having: access to another group of lines. The seized! connector will be operated in standard manner using its lower or normal set of wipers and banks.

Should the called: number he 2 132 then the connection will be extended through normal. wipers and bank of switches E and D and relay l8 of connector H will be operated to cause relay 52: to energize just before the vertical impulses to the connector. Relay 52 of the connector upon operating will cause the connection to be extended to the: second line. in. the second level oi the bank acces sible to'thewi pers 83, 84 andl85 of switcl'rlil". Shouldthe callednumber he. 222B then linea relay 48 will be operated. by the short. im pulse justbefore the. last. digit is sent to switch anditherefore after the: oil: normal springs 54; and. 55 have shifted to: their alternate contacts" so.- that relay 53' will bev operated to cause. wipers 86 87 and. 88 to: become: eilective.

The called number may also. be 221313 in: which case relay 48 will first operate. relay- 52 and then operate relay 53. toswitch the connection. via wipers 89. 90 and 91.

Thusit will be seen that the called number may have a letter interposed for any one of its digits, for any two: or three of the digits, or for all, and may be 2222,. 222B,- 22-132, 21522, B222, 131522,. Blane. or BBBZB- Also it will. be understood. that the connectors H ot the entire system. may be used. either witlr or without the relays 52 and 53 as is desired. And. in some cases only the first selectors may be equipped with double wipers andv banks. Inthe' usual. large. system it. will probably be suflicient toequip. only the first andisecond selectors with. such relays, especially in a time digit system. using first, second and third selectors. in which case the last three digits of the called; nunr her will. always be figures while the first two may beeither. letters or figures.

It will be seen therefore that. I: have pro.- vided; ayery efficient and flexible system. in which the groups may he greatly increased with only avery little change in thewiring of the various switches and also that I have provided a calling device which is. so constructedthat itwill. work equally well with switches of either type and.- may thereforebe installed to work in a mixed-systemin which only a partof the switches are given access to more than one group of trunks or lines.

hat I claim as my invention. is;

1. In av telephone system, a line, auto maticv switches accessible to the. line for ex tending a. connection. therefrom,- a calling device on the line for operating each switch in accordance with a digit of a" called. number, a pli-irality ofgroups of trunk lines accessible to: each. switch, one. group being normally accessible, and means in. the calling device for sending a preliminary set of rapid impulses to any switch prior to its operation in. accordance with. a digit, for rendering a group of said. trunlr lines accessible other than those normally accessible- 2. In a telephone: system arr automatic switch having aplurality of sets of wipers any one of which may be connected for use, a relay for" controlling: the connection of a desired set of wipers, circuit connection-s for short circuiting said relay when the switch is taken for use, means including a line relay for said switch for removing said short circuit and permitting the operation transmitting impulses at two different fre-' qu cncies to said switch over the two sides of said trunk line in series, a first selecting mechanism in said switch responsive only to impulses of one particular frequencmand a second selecting mechanism insaid switch responsive to mpulses of the other frequency. 7

4t. In a telephone system, an automatic switch having a plurality of wiper sets, an operating magnehrwi yer selecting mechanisin. a non-harmonic device responsive to low frequency in'ipulses to control said magnet, a harmonic device responsive only to high frequency impulses to operate said mechanism, and means for transmitting series of high and low frequency impulses to said switchto operate said devices.

5. In a telephone system, an automatic switch having a plurality of wipe'r sets, an operating magnet, wiper selecting mechanism, a non-harmonic device responsive to low frequency impulses to control said magnet, a harmonic device responsive only to high frequency impulses to operate said mechanism, a calling line, and a calling device at the station on said line for generating series of high and low frequency impulses to operate said devices.

6. In a telephone system, an automatic switch adapted to perform a plurality of successive selecting operations, a first selecting mechanism in said switch responsive only to high frequency impulses, a second selecting mechanism in said switch responsive to low frequency impulses, a trunk line terminating in said switch, and means for transmitting series of high and low fre-. quency impulses to said switch over said trunk line.

7. In a telephone system, an automatic switch adapted to perform a plurality of successive selecting operations, a first selecting mechanism in said switch responsive only to high frequency impulses, a second selecting mechanism in said switch responsive to low frequency impulses, a calling line, and a calling device at the station on said line for generating series of high and low frequency impulses to operate said switch.

8. In a telephone system, an automatic switch having primary and secondary movements, a plurality of groups of wiper sets for said switch, means for transmitting series of impulses of high and low frequency to said switch, means in said switch responsive to a series of high frequency impulses to select one of said groups of wiper sets, meansin said switch responsive to a se ries of low frequency impulses for operating said switch in its primary movement, means in said switchresponsive to a second series of high frequency impulsesto select a set of wipers in the selected group, and means in said switch responsive to a second series of low frequency impulses for operating said switch in its secondary movement.

9. In a telephone system, an automatic switch having a plurality of directive movements, a plurality of sets of wipers in said switch, means for transmitting alternate series of high and low frequency impulses to said switch, means in said switch responsive to the several series of high frequency impulses for selecting a particular set of wipers, and means in said switch responsive to the several series of low frequency impulses for directively operating said switch as set forth.

10. In a telephone system, an automatic switch, a line relay for controlling the operation of said switch, a plurality of sets of wipers in said switch, and a device comprising a tuned reed actuated by said line relay for controlling the selection of a desired set of wipers. v

11. In a telephone system, an automatic switch, a line relay for controlling the operation of said switch, a plurality of sets of wipers 111 said switch, a wiper selecting relay,-

and a harmonic device tuned to a particular frequency and adapted to be actuated by said line relay to control said selecting relay.

12. In a telephone system, a calling device having a plurality of operating means arranged in groups, low frequency impulse transmitting mechanism controlled by all of said operating means, high frequency impulse transmitting mechanism controlled only by operating means in a particular group, and an automatic switch comprising mechanism for performing two successive selecting operations responsive to high and low frequency impulses, respectively.

13. In a telephone system, a calling device having a plurality of operating means arranged in groups, low frequency impulse transmitting mechanism controlled by all of said operating means, high frequency impulse transmitting mechanism controlled only by operating means in a particular group, an automatic switch comprising mechanism for performing two successive selecting operations responsive to high and low frequency impulses, respectively, and a single line relay in said switch by means of which said mechanisms are caused to respond as set forth.

calling device for transmitting a preliminary series or high frequency impulses when the dial is operated from a finger hold me particular row, a switch at the exchange 'havjing a plurality of wiper sets, operating mechanism in said switch responsive to the said low frequency impulses, and wiper se lec'ting mechanism in said switch responsive I to the said high frequency impulses.

'15. In a --telepihone system, a subscribers line, a calling device at the station on said line provided with a dial havinga plurality of rows of finger holds, mechanism 'in said calling device for transmitting low frequency impulses when the dial is operated from a finger hold in one row, mechanism said calling device gfor'transmitting high frequency impulses when the dial is operated from a finger hold in another row, a switch at the exchange having a plurality of wiper sets, operating means the said switch responsive .to said low freuency impulses, aud wiper selecting mecianism' in said switch responsive to said high frequency impulses.

16. In a telephone system, an automatic switch -having two sets of Wipers, one set being normally connected and the other set benormally disconnected, a 'su-bscriber"s calling device dial having two rows of finger holds, means responsive to the operation of said dial from any hole tosend low frequency impulses to said switch to operate the same,

tmeans effective only in case said dial is operated from a hole in a "particular row for sending a series of high frequency impulses to said switch, and means in said switch .responsive to the high frequency 'im .ulses for connecting one set of "wipers :and Sr disconnecting the other set.

17. In a telephone system, an automatic switch having a plurality of sets of wipers, a calling device associated therewith having means for transmitting a series of high frequency impulses on its torwardmovement to select-a particular set of wipers, irrespective of the number of impuisesin the series, and

for sending one or more impulses on its baclc ward movement to move said wipers.

18. In a telephone system, an automatic switch having a plurality of wipersc'ts, a calling device associated with said switch having means for transmitting high and low frequency impulses to said switch, means in said switch responsive to low frequency impulses to position said wiper sets in accordance with the number of iow frequency impulses transmitted to it, and wiper selecting means in said switch responsive to select the same wiper set regardless of the'number of high frequency impulses transmitted to it.

Signed by .me at Chicago, in the county of Cook, State of Illinois, this 5th day of July, 1920.

'WILLIAM WALTER OWEN, 

